1. Field of the Invention
The present invention relates to methods and systems of smoking liming an engine.
2. Background Art
Federal Test Procedures (FTP) for engines may included tests related to analyzing smoke emission during varying operating conditions. Such smoke control tests may be directed towards determining black smoke emissions associated with poor air/fuel ratios (AFRs). The ability to control AFR during testing is critical to controlling smoke spikes and other undesirable engine emissions.
Boost-based smoke control is one AFR control methodology that relies on boost pressure to set an AFR that is appropriate for smoke control, i.e., one which limits or otherwise controls the amount smoked produced, such as to facilitate passing the above-identified emissions testing. Boost-based smoke control typically relies on boost pressure as an indicator of how much fresh air is available for combustion and determines the AFR as a function thereof. But, this method is limited to environments where no exhaust gas recirculation (EGR) is used since it is only in those environments that the trapped air in the engine cylinders is approximately proportional to the boost.